The method of drying lignite coal and unit for implementing the drying lignite coal method

The method of drying lignite coal and unit for implementing This drying lignite coal method is the subject of the invention.

Lignite coal due to its humidity exceeding even 60 %, is a fuel that can hardly be sold away, not to mention another country. Because of that the very only possibility of new application for using the lignite coal i.e. other than in power industry, located close the mine site, is to increase calorific value by drying.

Enterprises applying the lignite coal in their production, are managing with the problem of its high humidity differently. Plants using briquette employ drum driers that work in continuous rotary motion of the drum. Such a device requires the permanent inflow of the raw material to drying. This makes work on the dried stationary deposit of the drier out of the question. Moreover device requires to be installed in a suitably big floor, in a separate area hazardous one due to the flammability when dried because of vent system that vents fine coal in hot exhaust gases from the boiler at temperature ranging 700 ⁰ C. It excludes possibility of checking humidity. It is necessary to repeat the cycle again. It may happen material is over dried. The process of such drying is running as follows: placed to the drum, with axis parallel to the level, it is being poured from above, next fine coal grinded down due to the drum's rotation to its end. All the time the drum is ventilated with exhaust fumes from the furnace placed in the neighbourhood. Different variants of this process are described for example in the patent specifications from the USA numbered 4235174, 6193768 or 6412188.

Another method, applied widely in power stations powered with lignite coal is a drier named popularly pipedrier ¹ . Fine coal going down in the pipe is effected by a flow of exhaust fumes and air being afire. After going through pipe drier coal is dried additionally in the mills also with hot exhaust fumes and with hot air. Faults or also character of the functioning of such a device is limited possibility of additional drying only in arrangements energy, of generating the electricity. Average decrease of humidity in the pipe drier is limited and it is staying on the humidity level only about under 5% Appropriate drying is taking place in the power station in the mill. Damp separated from the lignite coal, it is already hitting in the figure of steam to the pot, however coal dried off is left hot through burners in that furnace. Such coal is grinded down so firmly is fit only for burning in the power boiler.

Both pipe drier as well as the mill closely with the full moon very much functions, also out of drying line, in the process of preparing fuels to burning in power boilers.

There is another method called fluidization using hot air and/or the exhaust fumes of coal deposits in special aeration chambers. This method is described for example the in US 46288833 specification.

To find in specifications it is also possible information about squeezing water from coal with special presses. For example this process was described in an Polish PL319381 application for a patent. In this solution reduction in the content of water in it relies on the containing water, grain lignite coal on it, that spread flat, into figures of the deposit, lignite coal is giving up, for applied mechanically, initial surface pressure which is lying lower down maximum, stepping out in the way, the pressure surface and a thermal energy is being led to it behind the itlp of steam which is surrendering of the condensation and it is warms the lignite coal up. Next, without more distant supplying steam, a surface pressure is being increased to at least 2.0 MPa, squeezing water, contained in the lignite coal that has been warmed up.

All Thise methods have one shared feature. A very high demand for the thermal energy is the reason.

A way being characterized by it, of drying the lignite coal is a being of the invention, that after filling the lignite coal in to drying column, through coal transfer there is a warmed air of the humidity inflicted to achieving the moment by the raw material, in addition the circulation is causing airs in the chamber of the drying room that warms it, going through layers of the lignite coal repeatedly portion of air circulates in the chamber as a long way, until it achieves the maximum saturation with steam, what sit is being removed after on outside chambers or drained by cooling the warmth on the exchanger and warmed again to the working temperature. It is important also it, that trend of the circulation of air in the drying chamber perhaps to be turned away in the time of drying the cycle. Process of drying it/sit is running cyclically that is cooling coal and emptying the column are coming after finishing drying the cycle, then loading the next portion of coal and the next cycle. The process of drying is running in the different variant into the continuous way i.e. systematically coal dried off is being picked up and the free space filled in is wet coal.

A device being characterized by the fact that it/sit contains, for drying the lignite coal with the above way is also essential at least one module making up from surrounding the column suszarnicz ¹ chambers with the casing insulated thermally in which a column is put for the central part and on the entire breadth of the drying chamber, on the part of the working zone drying columns one each or after both its sides are put heaters and fans about reverse characteristics of the work, dividing the space into chambers to the upper and bottom part. Through lengthening the sequence of exchangers

of the warmth, fans and the existing column perhaps to be enlarged freely or repeatedly on the breadth, and through putting them at right angles to the stream of air, to be extended perhaps parallel to the existing column and on the entire breadth of the chamber for the repeated number of columns. It is important, that drying column it is a metallurgical cuboids opened from the bottom with the chute crater or the floor drawn aside in addition it is possible in the column to favour three zones: first it is a zone chute, situated in the sticking out above the chamber, upper part columns, second it is a working but third zone put in the centre it is a zone being found at the bottom of the chute. In the of the zone chute area is so well-matched that the layer being the wet lignite coal is building buffer closing the space above zone working, keeping from getting out of warmed air of drying rooms. Area is found in the zone of the chute, at the continuous work of chilling which cold air chilling the lignite coal dried off is being supplied to.

It is essential, that in the inside of the column, small roofs made in parting walls of the column are fastened with horizontal layers there are holes intake, which warmed air and exit holes, which air is getting out through are getting to the middle of the column through oneself around columns, in addition both intake as well as exit holes are made with layers in addition under everyone with the small roof is found intake or exit hole arranged into this way, that if bottom layer or layers of small roofs is equipped with holes intake, it is layer put right is equipped with exit holes. Intake holes are found after both sides of the column around with it, that on the diagonal of its right. Exit holes are found after both sides of the column with it, that on the diagonal of its side.

It is important, that depending on direction of the rotation of fans after every sides are found on one part from sides of the column columns intake holes, however exit holes are found after the same side of the column on the second part of the side, also, in addition holes are intake after the diagonal at the righthOt with the account of oneself, exit holes like all sides of the column on either side and on both sides of the column, are also a reason of oneself at the height after the diagonal.

The object of the invention is depicted in the drawing, on which of fig. 1 a block diagram of the process of drying, fig 2 is showing cross section of the drying room equipped with one drying column while fig. 3 is depicting the principles of operation for drying section.

The lignite coal is burying itself to the drying column in order to create preventing buffer above the working zone of the column of air warmed for getting out outside the drying module. Fans are extorting the move after filling the column in airs, which going through heaters is getting the optimal temperature for the planned process of drying. Next columns are being crammed through holes in the working zone and it is sucking air warmed alternately out in repeated circulation. It relies on with the fact that it is being sucked out into dependences on direction of the rotation of fans, air of the around one part of the height of the column, then heights crammed in the second

part of the column. Pointed air is going through the lignite coal this way in the column and after for itrdirected as the sucked stream for the second side, already through fans and the exchanger of the warmth, is changing the direction of movement about 18Oo and again it is hitting into the column, treat as air crammed into small roofs $NP$ disease on its different part for the height. The movement of air consists in the inside of the column with small roofs covered with channels on migrating from above and is coming across columns to the obstacle to the figure of the parting wall. Local height it is causing pressures of air that it is escaping around under of channel covered with the small roof on entire its lengths and permeating layer the lignite coal is being gotten to formed channels under small roofs of taller layer which, it/sit is migrating to holes with exit. Passing air through the layer of the lignite coal is becoming permeated with the damp charged from it. Air circulates in the chamber as a long way, until it achieves the maximum saturation with steam, what it is being drained by cooling after on exchanger of the warmth and warmed again to the working temperature. Permeated air can be exchanged directly also to the fresh air. Then sucking the fresh air going through the cross exchanger is thrown away from the outside around chambers with permeated air being afire. Also a swapping of airs is possible without warming air sucked with air being afire, saturated with the damp. Permeated then, being afire air is being retroacted by the exit window directly to the atmosphere, however fresh air is hitting from the outside out of the intake window directly to the column which, it is starting in circulate, and coming across on exchangers of the warmth is happening with the drying air, all the way to the moment of the maximum acceptable satiation oneself with damp from coal dark brown. This process is repeated by the raw material to achieving the moment for the set humidity. It is also important, that trend of the circulation of air in the drying chamber perhaps to be turned away in the time of drying the cycle. The process has continuous character that is supplementing the column for contents is possible drying with wet lignite coal and picking coal dried off up without of breaking the process of drying. It is possible thanks to gravitational dropping of the lignite coal dried off on the bottom of the column and of regular work of chute elements in the zone of the chute of the column. Leading the process into the cyclical way is also possible.

The deposit dried then of the lignite coal is preserved into the stationary way. Contents are becoming empty after finishing drying columns from the dry lignite coal into This way, that as a result the own weight and the pressure finding layers of wet coal oneself in the zone chute dry coal is sliding to the bottom zone of the column. Introduced in the case in the drawing, being found in the bottom of the column has the crop team which the shape of the crater equipped with the closed hole has for the bottom zone through which dry coal is spilling out to a conveyor belt or the cart.

A drying room is essential to the realization of This way, in This case about the modular structure. Module of the drying chamber, which can be installed in production halls without burdening them for the structure or function perhaps as standalone building in the fresh air. The device consists of the drying chamber with around at least one drying column ¹ and of space after both sides opposed to itr, of the casing insulated thermally, windows of the swapping of airs, the exchanger of the warmth at least after for one side of the working part, fans about changeable direction of the sequence also as least one each for side of the column. Windows can cooperate on the principle of the cross exchanger, i.e. fresh air sucked from the outside chambers, is going through exchanger, with permeated air being afire retroacted from the drying room. Also a work of windows is possible without the recycled material of the warmth around of permeated air being afire in the purpose of preliminary air sucked to the drying room. Then saturated air is being removed by the exit window directly to the atmosphere, however atmospheric air is hitting directly to the chamber.

In the central zone of the drying chamber, on entire a column is found for the breadth for drying, and for precisely its main part - working. However spaces, which exchangers of the warmth are installed, in are found after opposite sides of the column axial fans and installations monitoring the temperature and the humidity of air and the so-called humidity balance ¹ . These spaces they are essential about the rear that a change in direction of the flow of air is coming in them through the column thanks to the axial functioning of fans.

With fundamental element of the drying module there is a drying column. Drying column is opened from above metallurgical cuboids from the bottom with the chute crater or the floor drawn aside. It is possible in the column to favour three zones. First it is a zone chute, situated in the sticking out above the chamber, upper part of the column, second it is a working zone put in the centre, and third it is a zone being found at the bottom of the chute. Zone chute These are walls led [sb out above the drying room of the drying column that they can be equipped with elements facilitating slipping down additionally of wet surface of the lignite coal to the working zone of the column. Height of the zone chute is so well-matched that the layer being in the wet lignite coal is building closing buffer space above zone working, keeping from getting out of warmed air of drying rooms. In the inside of the column, metallurgical small roofs are fastened with horizontal layers. Intake holes are made in walls of the column, through which to the middle of the column is being gotten warmed air and exit holes, which air is getting out from the column, in addition through on one level intake and exit holes are found after opposite pages of the column. Both intake holes as well

as exit are made with layers. An intake or exit hole is found with the small roof under everyone arranged into This way, that if the bottom layer of small roofs is equipped with intake holes layer put high is equipped with holes exit. So layers living next door of small roofs are moved about half a module towards themselves coal filled in from the mountain of the column dark brown, spilling out of the edge of the small roof of taller layer is falling on the small roof of lower layer filling the space in between with small roofs of the column. Since small roofs are to opposite walls of the column, they are building channels, which of around one page they are finished with the intake or exit hole, on the other columns are closed with the parting wall.

Every layer of intake as well as exit holes is lapped in the different variant of the workmanship with the layer additional of holes put more low. Holes are smaller in This case and small roofs being found in lengthening them are formed in shape of the pipe not-closed at the bottom about the section of the triangle or the polygon. Lapping the arrangement of holes and small roofs is correcting the effectiveness making drying smaller size of dead zones of permeating air by the layer of the lignite coal.

Depending on needs, the localization possibility depending on organization of the company, drying room it is possible according to the invention to extend adding consecutive drying modules. Expansion of the drying chamber for consecutive modules, we can lead in three directions. There is disassembly of the side, perpendicular to exchangers of the warmth wall, fans with the first way and columns. Lengthening the row of exchangers of the warmth, fans is coming then and parallel to drying column. Whenever if the wall is not to be disassembled, independently working drying chambers can be effected then. In both cases expansion can but it does not have to be a multiplication of the the basic module. With different version expansions there is disassembly of wall parallel to exchangers of the warmth and fans. In this case between fans and exchangers and existing column, an additional column is fitted in. It is recommended, in order to between columns a space which will be shared at the height with the barrier came into existence creating two smaller volumes for the baulk with columns. In order to to aid the move of air between columns, they are suggesting mounting fans of demurrages. It is also recommended supplementing existing exchangers of the warmth for additional surfaces and/or mounting additional exchangers between with columns. The dividing the space into two volumes between columns, put barrier must be at such a height, in order to sit protected swimming streams of air on the contrary effectively between columns, before mixing.